A quick Google search revealed this: http://forums.zend.com/viewtopic.php?f=69&t=4420 which suggests this is a Bluehost-specific problem. There's a hacky fix in there you could try.
However I'm going to say that this shouldn't be an issue, as you shouldn't be using Zend Tool on your production server. It is for code generation, so you should be using this whilst developing apps on your local machine (or development server). What you put on your live hosting should be the finished project.